Grinding machine with automatic crush dressing mechanism



Dec. 28, 1948. v F. POLK GRINDING MACHINE WITH AUTOMATIC CRUSH DRESSING MECHANISM 4 Sheets-Sheet 1 Filed March 2, 1945 n... WWI

unglin M F J FZZZL ATTORNEY Dec. 28, 1948.

F. POLK 2,457,318 GRINDING MACHINE WITH AUTOMATIC CRUSH DRESSING MECHANISM Filed March 2, 1945 4 Sheets-Sheet 2 8 li WW 1m ATTORN EY Dec. 28, 1948. L. F. POLK GRINDING MACHINE WITH AUTOMATIC CRUSH DRESSING MECHANISM 4 Sheets-Sheet 5 Filed March 2, 1945 ATTOR N EY Patented Dec. 28, 1948 TENT- OFFICE GRINDING MACHINE WITH AUTOMATIC I CRUSH DRESSING MECHANISM Louis F. Polk, Dayton, Ohio, assignor to The Shel.-

field Corporation, Dayton, Ohio, a corporation of Ohio ApplicationMarch 2, 19 4 5, Serial No. 580,589

One object of the invention is the provision, J

in a grinding machine, of a grinding wheel truing device incorporating a rotatable crusher wheel arranged in a support which is pivotally mounted so that the crushes can be swung to advance it towards or retract it from the grinding wheel, and with provision for positively moving the crusher at a slow rate of feed into the grinding wheel ,to obtain the desired forming or truing effect.

Fig. 7 is a diagrammatic showing of the elec- ,trical connections;

Another object is a provision of a device of the character mentioned having means ior automatically moving the crusher in a straight path and with a comparatively rapid forward movement until the crusher engages the grinding wheel, and then automatically moving the crusher continuously at a comparatively slow rate of feed during the entire crushing or forming action on the grinding wheel.

Another object is the provision of a grinding machine having a grinding wheel and a cooperating workdriving o'r regulating wheel for centerless grindingwith a rotatable crusher adjustable for engagement with both of these wheels so that exactly the same form will be imparted to the two wheels.

Another object is the provisionof agrinding machine having a grinding wheel and a work regulating wheel, with a crusher adapted to crush or form both of these wheels and adjustable for engagement first with one-of the wheels and then with the other, in a controlled manner.

Other objects and advantages of this invention will be apparent from the following description, the appended claims, and the accompanying drawings, in which,

Fig. 1 is a top plan view, with some oi the parts broken away, showing the principal elements of a centerle'ss grinder with a wheel crushing device embodying the present invention;

Fig. 2 is a side elevation illustrating the grinding and work regulating wheels and the crusher support;

Fig. 3 is a side elevation of the crusher support, showing the crusher in a lowered position;

Fig. 4 is a vertical section through the crusher support on the line l4 of Fig. 3; v I

Fig. 5 is a top plan view of the crusher support;

' Fig. 6 is a vertical section on the line 8-6 of Fig. 5;

Fig. 8 is a detail diagrammatically illustrating the limit switches operated by the crusher sup- Fig. 915 a detail showing the toggle operated switchin the crusher support;

Fig.'10 is a detail showing a limit switch;con-

trolled by the locking lever, and

Fig. 11 is a timing diagram.

Referring more particularly to the drawings, in which the same reference numerals are applied to like parts in the several views, l0 designates a grinding wheel of a grinding machine. In the particular embodiment of the invention illustrated, the machine is a centerless grinder havin a work rotating wheel I I. It is understood that the workpieces to be formed to a desired shape are placed between the two wheels l0 and II, the grinding wheel being driven at a comparatively high speed of a few thousand R. P. M. while the work rotating or regulating wheel H is driven in the same direction at a comparatively slow speed. preferably in a range of from iiity to two hundred R. P. M.

As shown in-Flgs. 1 and 2, the grinding whee i0 is secured to an arbor l2 rotatable in a suitable bearing portion of the main frame ii of the grinding machine. This arbor is driven asby a belt drive M from the main driving motor it during grinding operations. The work rotating wheel I! is secured to an arbor l6 rotatably mounted in a slid'able head ll of the usual character, this head being movable towards and from the axis of the grinding wheel in to accommodate work pieces of ,difl'e'rent diameters. One end of the arbor it is operated by a'drive wheel l8 that may be turned by a belt or a chain driven from a shaft below it, {such shaft" being operated through change speed gear mechanism in the gear box i9. An electric motor 20 operates the gear mechanism, to drive the wheel I! at a suitable desired speed. A wheelguard as shown in Fig. 2 is preferably employed to cover'the two wheels. This guard, as shown, includes a stationary guard plate 2i which may be fixed on the frame l3, and an extensible section" 22 shown in its retracted position under the guard 'plate 2|, but normally, during the grinding operation, being projected out towards the right-and covering the upper portions of I 24 can be advanced or retracted by suitable means such as springs and the electric solenoids illustrated diagrammatically in Fig. 7.

The main frame I3 of the grinding wheel is provided with a fixed bracket 26 provided with a bearing for a rocking post 21 projecting from the rear side wall 28 of the crusher support or housing 29. Gear 33 is fixed to the outer end of the post 21 and meshes with worm ll operated from a gear head motor 32 on the bracket. This motor serves to rotate the post, the motor 32 being reversible so that the entire housing can be swung either towards the grinding wheel In or towards the work rotating wheel I l to position the crusher 33 between the axis of either one or the other of these wheels and the axis of the post 21.

Fig. 2 in full lines shows the crusher 33 swung for engagement with the grinding wheel l0, while the dot and dash lines show the position of the housing 29 when the crusher is arranged for engagement with the wheel I I.

The crusher 33 is carried for free rotation about its own axis and can be bodily moved into engagement with the grinding wheel as will be presently described, while the grinding wheel is stationary. The grinding wheel is then started and driven at a comparatively slow speed, preferably at the rate of about three hundred feet per minute, by an auxiliary driving motor 35. Due to the firm engagement of the crusher wheel with the grinding wheel during rotation of the grinding wheel, the crusher wheel will be rotated at the same peripheral speed as the grinding wheel, and the crusher, which is preferably constructed of steel, will crush the grinding wheel away bit by bit until the grinding wheel assumes a surface which is exactly complementary to the surface formation of the crusher. The annularly ribbed form that the crusher has, in the particular embodiment illustrated, is merely one example of a great many shapes that could be employed, dependent upon the shape to be ground on the work.

In its normal position the crusher housing 29 is arranged with an inclination as illustrated in full lines in Fig. 2, but with the crusher 33 in retracted position, as illustrated in, Fig. 6, so that the crusher is above the wheel guard position. The retractable section 22 of the wheel guard is pulled back to the position shown in Fig. 2 before the crusher descends into engagement with the grinding wheel. The movements of the crusher are controlled automatically by a crusher adjusting motor 31, see Fig. 6, and in accordance with the present invention there is provision for feeding the crusher towards the grinding wheel at a comparatively rapid rate so that the crusher may be brought into engagement with the wheel without loss of time even though the extent of travel may be considerable as in the case of a well worn grinding wheel. After the crusher contacts the grinding wheel there is a yielding action in the moving means as a result of which a comparatively slow speed feed is imparted to the crusher, and the moving means is locked against continued yielding movement. The crusher is then slowly forced into the grinding wheel at a speed that does not create a breaking pressure destructive of the grinding wheel, while the grinding wheel is operated slowly.

As shown in Figs. 4, 5, and 6, the crusher 33 is rotatable in a holder 33 which is slidably guided on a holder support 39 arranged on the housing 29, for movement of the crusher wheel towards and from the grinding wheel. The direction of feed movement of the crusher may, if desired. coincide with a line radial of the grinding wheel, as in the particular embodiment of the invention illustrated.

The holder 38 has a dovetail groove receiving one half of the holder support 39, which consists of a two piece slide formed of plate portions 40 and 4| secured to one another, the plate 4| being slidable in the housing 29. Fixed to the holder support 39 is a threaded boss 42 operable along a threaded adjusting shaft 43, the latter being rotatable on suitable bearings and with its upper end adapted for operation by a wrench. Rotation of this shaft causes the holder support to move upwardly or downwardly, and if the holder support 39 is fixed to the holder 38, the latter will have the same movements. However, at times, the holder 39 is relatively movable on the holder support 39, and yielding movement of the holder will take place. A spring 44 positioned between the projection 44 at the lower end of the holder 38 and the lower end of the holder support 39, normally act to yieldingly maintain the holder 38 in a lowered position on the holder support.

The holder support 39 has a horizontal groove 45 receiving a pin 46 on the end of a lever 41, which is arranged in a recess in the holder support and is pivoted on the holder 38 by a short shaft 48. The axis of shaft 48 is horizontally displaced from pin 46 as shown in Fig. 10. When the holder support 39 is lowered by rotating the screw shaft 43 until the crusher contacts the grinding wheel, resistance to further movement is applied to the crusher by the grinding wheel itself and the crusher holder 38 then remains stationary, the continued lowering of the holder support serving to compress spring 44. This relative motion of the holder 38 and the holder support causes the lever 47 to swing counterclockwise as viewed in Fig. 10 so that it moves away from and permits closure of a limit switch 50 controlling a solenoid relay G, which governs an indexing mechanism, controlled by a solenoid 64. This indexing operation, changes the downfeed of the crusher to a slow speed feed and operates the plunger of a solenoid 5|, see Fig. 6, which travels upwardly and straightens a toggle linkage 52, which moves a locking finger 53 into pressure contact with the lever 41, securing or looking the holder to its support 39. Any further movement of the support 39 will then produce similar positive movement of the crusher into the grinding wheel. This locking that takes place comes into effect automatically after the crusher reaches the grinding wheel and regardless of the extent that the crusher has to travel until that point is reached.

After the crusher engages the grinding Wheel, and as a result of the relative movement of the crusher holder on the holder support, slow speed rotation of the grinding wheel is initiated, the crusher being brought into firm contact with the grinding wheel while the latter is not turning. After the crusher engages the grinding wheel the latter is driven at a comparatively slow speed by the auxiliary motor 35 that operates through an overrunning clutch 54 so that this auxiliary motor 35 need not move when the main wheel driving motor l5 operates, during the grinding operation. The speed of operation of the shaft 43 is automatically changed so that it will be driven comparatively slowly after the grinding wheel is engaged by the crusher. The continuous slow feed in a positive manner that takes place during the crushing operation continues through a predetermined interval or through a predetermined number of revolutions of the grinding wheel sumcient to dress or form the wheel. The feed movement is then automatically stopped during continued rotation of the grinding wheel for a few turns, and then the direction of rotation of the shaft 43 is reversed to rapidly withdraw the crusher.

During the initial withdrawal movements of the crusher, the holder 38 is fixed to the holder support, but when the holder 38 is fully raised, the lock is automatically released by engagement of a release pin 55 with a fixed arm 55, see Fig. 6, the pin breaking the aligned toggle linkage 52 to release the locking pin 53, the solenoid 5| at this time being dcenergized. The spring 44 then lowers the holder 38 a little distance on the holder support. When the crusher is brought into engagement with the grinding wheel, and before the crusher operation actually starts, the coolant fluid is started automatically by an-automatic valve in the coolant supply pipe, not shown.

The variable speed adjusting motor 31 in the housing 29 has a geared connection to a clutch plate 51, free on the shaft 43. A clutch hub 58 keyed on the shaft 43 may be operated into engagement with the clutch plate. 51 to turn the shaft 43 comparatively rapidly in a direction dependent upon the direction of motor rotation. The shaft may be driven comparatively slowly from the motor through a speed reduction drive including the worm gear 59 and the clutch plate 60 free on shaft 83. The speed of rotation of the motor 31 is adjusted to such value that excessive pressure between the crusher and the grinding wheel is avoided, the pressure depending upon the grinding wheel size and its construction.

The clutch hub 58 is automatically controlled by an arm 8| moved by lifting and lowering rollers engaging and controlled by a cam 62 which has rotation required. Switch g supplies the solenoid 84 which turns the-cam 62 for operation of the clutch disc 58. Switch h controls the solenoid circuit 81 which automatically retracts the guard sections 22 and 24 from the wheels. Another switch b controls the solenoid 5| which governs recesses and camming surfaces. This cam is fixed first be swung and moved to form or true the regulating wheel H and then swing over and automatically move to crush the work grinding wheel l0. Normally the supporting housing 29 is in the position shown in Fig. 2, but with the crusher elevated on the housing. The crusher is automatically lowered by movement of the holder 38 on the housing 29, and is automatically withdrawn after the wheel is crushed. Following crushing ofthe regulating wheel and retraction of the crusher, the housing is swung over'to its normal position when it opens a limit switch 82, 83, that causes, a further sequence of crushing operations on the grinding wheel l0.

The motor l5 that drives the grinding wheel rapidly during the grinding operation is connected to a three phase supply source 66 through a switch a. This source also feeds through a switch b to the operating motor 35 which turns the grinding wheel ill at a reduced speed during the crushing cycle. The motor 20 that drives the regulating wheel is connected in parallel with motor 35 and the locking of the crusher holder to the holder support.

One phase of the supply line connects to the primary of a transformer 89 having a secondary circuit connected to lead lines 10 and II. The latter is connected to one side'of switch controlling relays A, B, C, D, E, F, G, and H which respectively control the operation of the switches having the corresponding small letters such as switches a, b, c, d, e, f, g, and h. The lead line 10 connects through a start switch H which is normally open, a normally closed stop, switch 13, a normally closed relay control switch hi to the motor controlling relay A so that when switch 12 is manually closed, in carrying out a grinding operation, the grinding wheel motor l5 will be energized during the grinding operation. The relay coil A closes a switch al to complete a holding circuit around thestart switch 12.

The lead line 10 connects through a start switch N when the latter is manually closed for a crush ing operation, and through a normally closed stop switch 15, then through limit switch 18 to the relay coil H. Although the operator would ordinarily stop the main grinding wheel motor i5 by operating the stop switch 13 before starting a crushing cycle, the deenergization of that motor is insured by the switch hi which is opened when the relay H is energized. When the relay H is energized it closes the switch h to energize thev wheel guard controlling solenoids 61! and retract the cover guard sections. When the relay H is energized it also closes a holding circuit switch b2 around the start switch 14. At this time, the switch 18 is closed, see Fig. 9, this switch I8 being temporarily opened for an instant or so later on in the cycle when the toggle arms move down from a straightened position, when the pin connecting the two toggle links causes clockwise movement of the pivoted lever 11. A switch 19 is also instantaneously operated under these conditions, this switch being in series with the relay At the start of a cycle of crushing operations, if both the regulating wheel and the grinding wheel are to be dressed or formed, the speed of the motor 20 that drives the regulating wheel II should be adjusted to a value low enough so that the wheel is not driven too fast in the crushing cycle, and the speed of the motor 20 is therefore adjustable or change is made in the gear reducing drive so that this condition can exist. At the start of the crushing cycle, the housing 29 is in its left hand position as viewed in Fig. 2.

A two pole switch 98 under the operator's control may now be moved towards the right. from the position, shown in Fig. 7, so as to close a circuit through a normally open switch 713, closed at this time because relay H is energized. Switch h3 connects through the switch 98, through a closed cam operated switch 91, through normally closed switch I I, through limit switch 84, closed at this time, and through the relay E to the other side of the line H. Switch 84 is carried by a post 25 on the slidabie head I! and is opened by the housing 29 only when the housing is swung over to the regulating wheel. Energization oh'elay E closes switch e and by energizing the motor 32, the housing 29 is swung over towards the regulating wheel II. The operation just described is during. the time interval from K to L in the timing chart, Fig. 11. At the end of this swinging movement, the housing automatically opens switch 84, deenergizing relay E and stopping motor 32.

It will be noted that when relay H. was energized the switch It was closed to cause retraction of the wheel guard. The housing is now over the wheel Main driving motor I is deenergized and switches 82 and 83 are closed.

When the switch 94 opened and relay E was deenergized, it closed a normally closed switch el, relay F, now deenergized, closing switch f3 so that a circuit will be completed to the lead wire through closed switches M, 98, el and 13. The various switches controlled by the several coils are shown in the position they assume when their respective coils are deenergized. Closing the circuit to the wire 10 causes the energization ofrelay C through a cam operated switch 95, the relay C closing switch c operating the adjusting motor 31 to cause rapid downfeed of the crusher towards the regulating wheel, the clutch hub 58 engaging clutch disc 51. This downfeeci continues until the crusher engages the regulating wheel and then the relative movement between the -crusher holder 38 and the holder support 39 swings the lever 41, closing limit switch 50 so as to energize the relay G which in turn closes switch a and operates the indexing solenoid. The movement of the cam 62 which this produces changes the position of the hub 58 so that it will engage the clutch disc 60, as shown in Fig. 6, and start to cause continued lowering movement of the crusher at a comparatively slow feed rate. At the time of engagement of the clutch hub 58 with the clutch plate 60, an arm 8| yieldingly held on the arm 6| engages and closes a normally open switch 89 which is in circuit with a timing motor 90. The shaft of this timing motor carries a series of cams which regulate switches 91, 92, 93, 94, 95, 96, and 91 in proper sequence. The operation of this cam shaft first closes the switch 93 which energizes the relay B to close switch b and produce rotation of the slow speed wheel drivingmotors 35 and 20, the crusher being in engagement with the regulating wheel at this time. This is at the location M in the timing chart illustrated in Fig. 11, and as indicated in that figure the energization of solenoid 54 is only temporary, as the continued operation of motor 90 causes the cam of switch 92 to promptly open again. At this same time, due to energization of relay B, solenoid 5| was energized to lock the-crusher holder 38 to the slide 39. The crushing operation is therefore started. At the location N the crusher feed motor 31 is deenergized by the automatic opening of switch 95 after the wheel has been crushed for a predetermined time interval, thus opening the circuit through the relay C. At this time, at location N, the indexing solenoid 64 is energized by closing switch 92 through operation of the timing motor 90, which thus causes another temporary energization of relay G. This shifts clutch hub 58 to a neutral position. At the point 0 in Fig. 11, after time has elapsed for several revolutions of the regulating wheel to take place, the timing cam. driven by motor 99. opens switch 93 deenergizing relay B and stopping the 8 crushing driving motors 35 and 20. After a sufflcient time interval for stopping the rotation of the wheel II, the indexing solenoid is again energized, see location P on the timing chart, by the time control switch 92 so as to switch the clutch hub 53 into engagement with the upper clutch disc 51, and at this same time at the point P the cam controlled switch 94 is closed by its cam,

energizing coil D to close the switch d and ener-..

gize motor 31 to operate it in a reverse direction, and this produces a comparatively rapid retraction of the crusher holder. The cam 94 is closed only momentarily, but the circuit is held closed through coil -D by holding switch d2 until the circuit is broken by opening switch I9 automatically later on as will now be described. When it is moved up far enough for the pin 55 to engage the fixed arm 59, the pin will break the toggle, releasing the locking of the holder with respect to the holder support, and the downward movement of the pivot pin which connects the two toggle links will temporarily open switches I8 and 19 by clockwise movement of the lever 11. This takes place at the location Q in Fig. 11. When the switches 18 and 19 open, the crusher feeding motor 31 is deenergized. Since the switch 82 is closed, opening the switch 18 will have no effect, but the opening of switch I9 will deenergize the relay D held closed up to this time by the switch 112 which was closed when the cam operated switch 94 first closed the crushing feed motor relay D. With the crushing feed motor 31 deenergized, the switch dl is returned to its normally closed position, cam operated switch 96 being closed at this time so that the relay F is energized. This closes switch f and energizes the housing swinging motor 32 to cause the housing to swing clockwise until it comes up against and opens the limit switch 82, 83 which immediately deenergizes this motor 32, leaving the crusher poised over the grinding wheel H).

A holding switch 9| is connected in parallel across switch to hold the circuit through timing motor after switch 80 opens, and until a cam on the timing motor opens this switch 9| at the end of a cycle. The switch 9| thus opened at location R during the return of the crusher support leaving switch closed. When switch 82, B3 is opened, relay F is deenergized closing switch f3 and completing a circuit through closed switch 95 to energize solenoid C which closes switch 0, and energizes the crusher feeding motor 31. The circuit through solenoid C is through closed switch 95, closed switch f3 (because coil F is deenergized by opened switch 93), the circuit being completed through closed switch el (coil E being deenergized) and through the blades of switch 98 which is still in its right hand position, then through closed switch 72.3, to the line side '19. Downward movement of the crusher towards the axis of the grinding wheel l0 then takes place (through the time S to T of the timing chart) until the crusher engages the grinder and there is a yielding movement of the holder 39 on the holder support. This again closes switch 59, energizing the indexing solenoid relay G through the closed switch 92. The indexing solenoid engages the clutch hub 59 with clutch plate 69 and produces slow continued downfeed of the crusher for a period of time determined by the timing motor 90. At the start of this slow downfeed the crusher driving motor 35 was energized by closing relay B under the control of cam operated switch 93 and the locking solenoid 5| was also energized, switch b being closed when relay B was energized. Cam operated switch 85 being closed, the downfeed continues for a time interval determined by motor 90. Switch 95 then opens to stop the continued slow downfeed movements of the crusher and deenergize the crusher feed motor 31. Switch 92'also closes, at location U on the timing chart, to shift the clutch hub to a neutral position. After a time interval switch 93 opens and stops the crushing drive motors 35 and 20 at location V. After a time interval, switch 92 closes again to shift clutch hub 68 to plate 51 and at the same time, at location W the motor 31 is energized through switch d. The crusher is thus retracted from the grinding wheel. When the holder 38 is fully retracted, the toggle linkage is broken automatically, the lock is released, and the switch 50 is opened preventing further energization of the relay G. When the toggle linkage breaks, switches 18 and 19 are temporarily opened, the opening of switch 18 temporarily opening the circuit through relay H, which also opens the switch n2 so that relay H will not be again energized when the switch 18 closes. Deenergizing relay H also opens switch M to stop the cycle (at X, Fig. 11). The opening of the circuit through relay H also deenergizes solenoid 61 to permit the spring return of the cover sections of the grinding wheels. The continued operation of the timing motor 90, energized through closed switch 9| carries the cycle from X to Y in Fig. 11, and then the timing motor itself opens switch 9|. The crushing apparatus is now ready for another sequence of operations.

If it is desired to only crush the grinding wheel and not the regulating wheel, the double pole switch 98 is moved to the position indicated in solid lines in Fig. 7, so that the current from the lead wire 10 to lead wire llll is direct instead of going through the normally closed switches 'el and f3. Now when the start switch M is closed. relay H is energized to retract the cover sections of the wheels, and close switches M and M as before. Switches 82 and 83 being now open, there will be no circuit through the relay F to energize the crushing swinging motor 32. The rapid downfeed' of the crusher holder will then take place, followed by the automatic change to a slow feed, then energization of the crusher de-* vice drive motors 35 and 2D, the locking of the holder to the holder support, the continued slow downfeed of the crusher, the maintaining of the crusher position during continued crushing, then the'deenergization of motor 31, the shift to neutral drive, the deenergization of motors 20 and 35 after a time interval, and the rapid retraction of the crusher holder as before. The cycle then stops at the completion of these operations, by opening switch 18 to break the circuit through the relay H.

It will now be apparent that the operation of the crusher, in its various movements, is automatically controlled so that the pressure applied to the grinding wheel, and the time during which the actual crushing takes place can be reset so that a proper crushing action takes place without requiring the control of pressures or time by the operator actually running the machine, once the proper adjustments have been made. It permits the operator to true the grinding wheel much more frequently than the regulating wheel is trued, since the grinding wheel will ordinarily wear faster than the regulating wheel. And, since the same crusher is used for both the grinding wheel and-the regulating wheel, both wheels will be given identical shapes.

- 10 While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus.

' and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A grinding machine having a grinding wheel and a rotatable crusher for forming the surface of said grinding wheel, a crusher supporting housing, means pivotally carrying said supporting housing for rotational adjustment of the crusher axis towards and from the grinding wheel, and

means for moving the crusher bodily in said support to feed the crusher into the grinding wheel, and mechanism providing for sequential -operation of said means to initiate the operation of one of said means after the operation of the other.

2. A grinding machine having a grinding wheel and a rotatable crusher for forming the surface of said grinding wheel, a crusher supporting housing, a crusher holder movably supported on said housing and carrying said crusher for rotation about the crusher axis, means pivotally carrying said supporting housing for rotational adjustment of the crusher and the crusher holder towards and from the grinding wheel, and means for sequentially moving said supporting housing pivotally on its carrying means and then moving the crusher holder along said supporting housing to feed the crusher into the grinding wheel.

3. A grinding machine having a grinding wheel and a rotatable crusher for forming the surface of said grinding wheel, a crusher supporting housing, a holder slidably carried by said housing and rotatably carrying said crusher for rotation about the crusher axis, means pivotally carrying said housing for rotational adjustment of the crusher axis and said holder towards and from the grinding wheel, operating means for positively moving said housing on its pivotal support, means for moving said holder on said housing to feed the crusher into the grinding wheel, and means for sequentially controlling the pivoting and sliding movements of said housing and holder.

4. A grinding machine having a grinding wheel and a cooperating work regulating wheel for centerless grinding, a rotatable crusher for forming the surface of said grinding wheel, a crusher holder on which said crusher is rotatably mounted for movement about its own axis, means for moving the holder to cause approach of the crusher to either the grinding wheel or the regulating wheel, and means for slowly feeding the crusher under positive control and with a continuous motion into one of said wheels.

5. A grinding machine having a grinding wheel and a cooperating work regulating wheel for centerless grinding, a rotatable crusher for forming the surface of both of said wheels, a crusher support on which said crusher is mounted for rotational movements about its own axis, means carrying said support for movement of the crusher towards either the grinding wheel or the regulating wheel, and means operable to positively move the crusher into one of said wheels.

6. A grinding machine having a grinding wheel and a cooperating work regulating wheel for centerless grinding, a rotatable crusher for forming the surface of both of said wheels, a crusher holder on which said crusher is mounted for rotation about its own axis, a support, adjusting means for moving said holder on said support,

adjusting the crusher axis towards either one of ,said wheels as desired.

including a yielding connection, and means for holding said yielding connection against yielding movements and automatically operable after the crusher engages the wheel to be formed to provide a positive continuous motion of the crusher into the grinding wheel.

8. A grinding machine having a grinding wheel and a cooperating .work regulating wheel for centerless grinding, a rotatable crusher for forming the surface of both of said wheels, a crusher holding means and a crusher supporting means mounted for sliding movements one on the other, a pivotal support for one of said means, and means operable to effect such pivotal and sliding adjustment of the crusher to move the crusher into effective engagement with either one of said wheels as desired.

9. A grinding machine having a grinding wheel and a cooperating work regulating wheel for centerless grinding, a rotatable crusher for sequentially forming the surface of both of said wheels, a crusher holder on which the crusher is mounted for rotational movements about its do Number 32 own axis, a support slidably carrying said holder, means pivotally carrying said support for rotational adjustment of the crusher axis towards and from either the grinding wheel or the regulating wheel as desired, operating means including a yielding connection for moving the holder on the support to rapidly advance the crusher to the wheel to be formed, and means operable to prevent yielding movement of the yielding connection automatically after the crusher engages the wheel.

10. A grinding machine having a grinding wheel and a cooperating work regulating wheel for centerless grinding, a rotatable crusher for similarly forming the surface of both of said wheels, a crusher holder on which said crusher is mounted for rotational movements about its own axis, a support slidably carrying said holder, means for slidably moving said holder on said support, means pivotally carrying said support for rotational adjustment of the crusher axis, means operable to swing said support about said axis, limit switches operable by said support for automatically stopping the swinging movement in limiting positions, and means controlled by said limit switches for initiating movement of said holder on said support.

LOUIS F. POLK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 2,135,202 Scrivener Nov. 1, 1938 

